In portal axle systems with a portal axle of this type, the brake disk is arranged radially inside of the key of the wheel rim, and the brake disk is surrounded by the brake caliper of a disk brake at its radially circumferential outer contour. This means that the maximum dimensioning of the brake disk is limited by the inner diameter of the key of the wheel rim. When smaller vehicle wheels are used for the vehicle, the rim is also reduced in size so that the diameter of the brake disk must also be reduced. In known portal housings, the drive wheel, the intermediate wheels and the output wheel are introduced into the portal housing through an orifice coaxial to the output shaft in the wall of the portal housing on the hub carrier side and mounted therein. This means that whichever gear—the drive wheel, intermediate wheels or output wheel—has the largest diameter determines the diameter of the orifice. However, the diameter of the orifice also determines the radial distance of the outer contour of the portal housing in the area of the orifice from the rotational axis of the output shaft. This outer contour in turn determines the smallest possible radial distance from the output axle in which the brake caliper of a disk brake can be arranged. But this also means that not any small vehicle wheel can be used because the smallest possible distance of the brake caliper of a disk brake from the drive axle must be met.
Therefore, it is an object of the invention to provide a portal axle which makes it possible to use vehicle wheels having a small diameter.